Split sslhaf core functions to a lib, removed deps on apache + apr

Rebased to include your recent commits, with much less changes to the internals.

The changes are:

* Unix line endings: changes almost every line, so good to get in first
* Split core logic into a separate libsslhaf: I simply borrowed the autotools collateral from libhtp for this. I'm quite awful at doing this sort of thing, I have little experience with autotools, so it will pay to give this an expert look
* Remove dependencies on httpd-devel and apr: This is done in most part by replacing direct library calls with calls to pluggable callbacks. The user of libsslhaf can easily plug in standard c library or as in the case of mod_sslhaf, apr library calls. In addition to being useful for reducing dependencies, this feature allows library users to receive logging messages from the library and emit them with their applications' logging mechanisms. Also, it allows library users to uphold a consistent memory allocation strategy in their applications, for example memory pools.
* Some cosmetic changes such as namespacing macros and functions.